The present invention relates to a method of detecting the condition of a liquid layer level in a case where a plurality of liquids are in a layer condition.
In a fat-splitting tower, water is fed from its upper portion, oil such as fats and oils or the like which is smaller in specific gravity than the water is continuously fed from its lower portion, the oil and the water are brought into contact under a thermal source by steam so as to cause hydrolysis reaction for splitting the oil. By the difference in specific gravity, the oil exists in the upper portion, and the water exists in the lower portion, thus causing a interface where they are in contact with each other.
If the interface rises higher than a proper level, the residence time of the oil within the tower becomes shorter so as to deteriorate a reaction (oil splitting) factor. If the interface lowers, the oil is mixed into the exhaust water so as to lose the oil. Therefore, it is necessary to correctly, know the position of the interface. Thus, the layer level condition is periodically assured by an visual inspection of the liquid sampled from portions in the vertical direction of the tower.
But in the visual inspecting operation of the liquid sampling, it is difficult to determine the layer condition with a time series comparison, because the sampling marks are restricted. Although there is a method of detecting the interface from the measurement of specific gravity, electric conductivity, light transmission degree or the like which is caused by the oil and the water, it is difficult to detect the interface by these measurements when a system as a whole is high in temperature and pressure, and dirt as well as emulsification are large in extent.